"Even if it may not lead to anything, it keeps us with the hope that we still will find him." The 18-year-old left Miami to study Biomedical Engineering. He was last seen on Thursday. Police are asking business owners to look for clues.

"He may be injured," said Tscharna Senn of the Gainesville Police Department. "And if he's injured, we need to try and find him as soon as possible."

The college freshman just graduated from the Doral Academy Charter High School. Former classmates have headed up to Gainesville to aid in the search.

Christian's father said a friend admitted to beating his son and then retained a lawyer after being committed for a mental health evaluation. He's said to be suicidal. That friend claimed he left him in a wooded area.

Police suspect foul play.

"He's still alive," said his father. "And he's out there. I cannot do it by myself, even though I'm going to try, that's all I can say."

Police have identified the last person to see Christian Aguilar was a former classmate named Pedro Bravo. No charges have been made in this case.